Vice President Joseph R. Biden said Tuesday night that Republican presidential frontrunner Donald Trump and his rivals will help Americans address racism by inundating voters with their divisive rhetoric.

“I want to thank Donald Trump,” Mr. Biden said to laughter at a Black History Month reception he hosted at his official residence. “The stuff he’s doing, and others, the stuff [Texas Sen. Ted] Cruz is doing. He’s making the American people look in the mirror.”

Mr. Trump caused a flap on Sunday by initially refusing to disavow former Klan figure David Duke.

Referring to “divisiveness” in the GOP race, Mr. Biden said, “maybe it’s a good thing, to awaken the American people about the subtle and not so subtle deals going on.” He said the campaign rhetoric was not only about African-Americans, but also Muslims, gays and the immigration debate.

The vice president said he had been watching Super Tuesday early voting returns on TV just before addressing his guests.

“Watching what’s happening now, I think you’re going to see a real opportunity for us,” Mr. Biden said. “The American people are honest. And they look in the mirror and see what’s looking back at them. If we’re smart, and we’re lucky, I’m convinced that the American people are prepared over the next decade to gradually to deal with institutional racism.”

Among those attending the reception were Rep. Charlie Rangel, New York Democrat; former NBA star Dikembe Mutombo; Marian Robinson, mother of first lady Michelle Obama; and Rep. John Lewis, Georgia Democrat.